Since battery-powered hand-held power tools enable a high flexibility during operation, as they are in particular independent from mains power and thus outdoor jobs may also be comfortably carried out, it is conventional to utilize battery packs during operation of a hand-held power tool.
Battery packs of this type are basically known and have rechargeable batteries, generally a plurality of battery cells connected in parallel and/or in series. In relation to this application, a battery pack is thus understood as a battery packet, which is composed of multiple electrically interconnected battery cells and may store electrical energy, deliver the energy necessary for operating the hand-held power tool, and may be mounted interchangeably on a hand-held power tool.
In general, a temperature signal and coding resistance values are transmitted, in addition to the voltage, during contacting of the battery pack with the hand-held power tool via contact elements consolidated in an interface.
An interface should be understood in particular as a device which is provided to directly or indirectly establish an electrical and, in particular, a mechanical connection to a charging device and/or a hand-held power tool.
The temperature signal is used for monitoring the battery pack cell temperature during the charging and discharging process. With the aid of the coding, the battery pack may be identified with respect to the charging device and the discharge side, i.e., the hand-held power tool, since the battery packs are usually configured specifically for a certain hand-held power tool. Other battery packs, which are not provided for the hand-held power tool, e.g., those with a different nominal voltage, may not be accepted on the part of the hand-held power tool so that the battery pack and/or the hand-held power tool are not damaged.
Coupling the battery pack to the hand-held power tool takes place by plugging or inserting the interface of the battery pack into a complementary plug-in socket of the device housing. The interface has contact slits in which contact elements may be situated. If the energy of the battery pack is consumed, then it may be removed and connected to a charging station having corresponding counter-contact elements. If multiple battery packs are available, it is thus possible to remove the discharged battery pack from the hand-held power tool and exchange it for a charged one.
The battery packs and also the hand-held power tools and charging devices, and thus the respective interfaces, are subject to constant further development, during which it is common that additional contact elements and counter-contact elements are to be implemented in the interfaces in order to exchange additional information between the devices. It is thus desirable, for reasons of manageability and handling of the battery pack and also the hand-held power tool, to keep the installation space necessary for the interface as compact as possible. In addition, for reasons of the compatibility with previous models, the demand arises, if necessary, that the geometry of the interface is to be changed as little as possible with respect to a previous model.